The invention concerns a radio frequency (RF) coil system for a nuclear magnetic resonance (MR) measuring means, in particular an MR tomograph, which comprises a magnet coil system for the generation of a homogeneous magnetic field along a z-axis in a measuring volume within the MR measuring means and, if required, a gradient coil system for the generation of preferably linear magnetic field gradients in the measuring volume.
Such an RF coil system for an MR tomograph is e.g. known from U.S. Pat. No. 4,939,465.
Up to now, conventional RF coil systems of this kind have always been constructed in an axially continuous manner, such that lateral access to the investigation volume via the RF coil system was hardly possible. For this reason, it is e.g. extremely difficult with conventional RF coil systems to carry out minimum-invasive surgery, from the side, on a patient inside a tomograph, since there are always obstacles, like rods, bars and other coil parts of the RF coil system blocking the way. It would also be desirable to integrate in the RF coil system adjustment rings, fixing rings or support rings, which could support e.g. biopsy needles, laser means for coagulation, surgical instruments and the like or enable the exact determination of position or the positioning of the investigation object in the MR measuring means, such that the RF coil system, with its minimum radial distance from the z-axis, can get as close as possible to the surface of the measuring object.
For this reason, it is the object of the present invention to present an RF coil system of the initially described manner which allows lateral access, in the radial direction, to the investigation volume and/or provides the possibility to integrate into the RF coil system an adjustment ring, a fixing ring or a support ring surrounding the investigation volume.